In underfill curing of a flip chip package, a high temperature during processing can induce warpage of the flip chip package. Due to a cross-link chemical reaction of underfills after a full curing process, the warpage can be increasing to around 1000 μm or more in some cases. High warpage not only causes high internal stress, high warpage will also become a challenge for wafer handling during a following process. For example, the high warpage can result in a die cracking issue during a molding compound grinding process.